First West Nile infected mosquito of 2025 detected during routine surveillance in Tarrant County

Fort Worth, Texas – Tarrant County Public Health has officially confirmed the first mosquito sample to test positive for West Nile Virus (WNV) this year. The sample was identified through routine mosquito surveillance, signaling the start of the 2025 West Nile season in the county.

Warmer Months Bring Higher Risk

As temperatures rise from May through October, mosquito activity also increases — and with it, the threat of West Nile Virus transmission. Health officials stress that while many people infected with the virus show no symptoms, some do. “While most people infected show no symptoms, about 1 in 5 may develop fever, headache, body aches, or joint pain. In rare cases, the virus can cause serious illness affecting the brain or nervous system.”

The virus is primarily spread through mosquito bites, making prevention efforts especially important as the season begins.

Simple Steps Can Help Prevent Infection

Tarrant County Public Health urges all residents to take proactive measures to protect themselves and reduce mosquito populations near their homes. These include:

• “Applying EPA-approved insect repellant when outdoors.”

• “Wearing loose fitting long sleeves and pants, especially during dawn and dusk when mosquitoes are most active.”

• “Removing or treating standing water around your home or property. Mosquitoes only need a teaspoon of water to reproduce.”

• “Staying indoors during peak mosquito activity hours, like dawn and dusk, when possible.”

Residents are encouraged to stay alert and informed as the season progresses. More information about West Nile Virus and prevention tips can be found on the West Nile Virus webpage of Tarrant County Public Health.